In particular, Ibn Khaldun of Tunis (1332-1406) wrote on economic and political theory in his Prolegomena, showing for example, how population density is related to the division of labour which leads to economic growth and so in turn to greater population in a virtuous circle.

Marxisteconomics is usually classified as a variant of neoclassical economics and is based on the writings of Karl Marx.

J.S. Mill was an economist, a Classical economist whose magnificent 1848 restatement of Ricardo's theory was thought to be so conclusive that, in the beginning of a discussion on price theory, he confidently notes that: